#!/usr/bin/env python
# @FileName :1_14_homework.py
# @Time :2024/1/14 11:41
# @Author :niecailing
#输入任意一串字符，统计字符a出现的次数
str1=input("请任意输入一串字符：")
a_count=0
for i in str1 :
    if i=='a':
        a_count+=1
    else :
            pass
print(f"a字符的个数为{a_count}个")